The goal of our research is to elucidate the mechanisms that establish cAMP compartmentation in controlling signaling specificity as well as determine the functional importance of cAMP microdomains. cAMP mediates many cellular processes by coupling to downstream effectors such as cAMP dependent protein kinase (PKA) and exchange protein directly activated by cAMP (Epac). Because cAMP is produced at distinct subcellular sites and diffuses rapidly throughout the cell, mechanisms must regulate signal propagation in order to achieve a desired cellular response. However, only recently have tools become available to effectively explore these mechanisms of control. Impaired cAMP signaling has clinical implications such as obesity and type II diabetes. Therefore, a better understanding of cAMP signaling may lead to new therapeutic approaches for these clinical conditions. The specific aims of our research are to further develop and characterize FRET-based cAMP indicators to elucidate the spatiotemporal dynamics of beta-adrenergic receptor signaling and use these indicators and in vitro assays to determine the downstream effectors and functional significance of mitochondrial cAMP. [unreadable] [unreadable]